Saturday, February 5, 2011

Porcupinefish


Porcupine fish are almost cartoon like in their appearance. They belong to the family Diodontidae. They are closely related to pufferfishes, but possess big heavy spines on their body. They are found throughout the world in shallow temperate and tropical seas. They range in size from 7 to 50 cm depending on the species of which there are around 15.

Porcupine fish are slow and as a result are unable to escape very easily from predators. One evolutionary tactic that they have up their sleeve is the ability to blow up their body by gulping in water to their gut. In larger species the spines then become erect whereas small species always have erect spines. They can double their size, and it helps to avoid been eaten since they are then hard to swallow (with the added help of been covered in spines). Here is a good example of how such a tactic works.



If this wasn't enough some species are also poisonous, with the neurotoxin been produced in their organs such as the liver. The tetrodotoxin is 1200 times more potent than cyanide!!! Interestingly, this poisen is likely to be produced by bacteria which are taken in through the animals diet. Evidence for this comes from the fact that porcupine fish in captivity are not poisonous. Despite all these defense mechanisms sometimes they do fall prey to sharks or orcas.

Despite been slow these fish are highly manouverable as is evident when watching them feed. Many come out at night searching for their favourite prey.....mollusks. To our eyes the prey may not be obvious but the porcupine fish will detect their prey, position themselves over the sandy spot, and blow water over the sand exposing their dinner. It could be that porcupine fish detect water jets of their prey that are produced as they breathe out water and this is why they are able to detect them from under the sand.
Porcupine fish have a mouth that in appearance resembles a beak, which is actually made up of fused teeth. This set up is ideal for crushing up the shells of mollusks.
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Friday, November 26, 2010

Deep Sea Creatures

In 2009 I went out on deep sea fishing vessels in New Zealand as a scientific observer. Although the conditions were tough you did get to see fish species that you probably would never encounter under any other conditions. Here are some of these strange sea creatures. 

Giant Black Ghost Shark


Electric Ray

 Fur Seal
Cape Pigeons
Thresher Shark
Porcupine Fish
Sunset
Elephant Fish
Sunfish
Sealion/Albatross
Prickly Dogfish
Dealfish
Lizardfish
Blobfish
Whale
Elongate Dory
Scaley Stargazer


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Tuesday, November 23, 2010

Postdoctoral Research Begins - Finding Sites

In the last week I have begun to work on my new postdoctoral research that focuses on how elevated turbidity levels can impact on exotic and native fish populations. This work forms part of a grant that I was awarded earlier in the year, and will continue to fund me for the next few years.

I arrived back in New Zealand this last Saturday and have been looking at sites to initiate field sampling. I will be working in the Waikato River in New Zealand. The Waikato River is the longest river in New Zealand running for 425 km in the North Island. It has a strong turbidity gradient that I aim to sample fish biodiversity along. Some site searching managed to turn up some turbid sites and some clear water sites. Here are some pics.

Whangaparino River Turbid Site



Waikato River Turbid Site




Waikato River Clear Site



Koi Carp Feeding In Turbid Waikato Tributary


video



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Tuesday, November 2, 2010

Sustainable Seafood

We are told time and again that we need to eat more seafood for a healthier diet. But how does this work when, globally, fish populations are in massive decline. Barton Seaver, sustainable seafood advocate and chef, gives his opinion in this 10 min video. Enjoy.


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Should Fishing Be Protected?


So here is an interesting topic, which is bound to produce anger and anxieties on both sides of the fence. Today (Nov. 2) voters in Arizona, Arkansas, South Carolina, and Tennessee are going to the polls to decide whether hunting and fishing should be protected under each states constitution. When something is protected then it becomes very difficult for the courts to take that right away from you. So by doing this today it is ensuring that fishermen will have a right to catch fish for future generations. 

This has largely come about because recreational fishermen have become fearful of recent attacks by PETA (People For The Ethical Treatment Of Animals) who have campaigns against fishing - viewing it as cruel and unnecessary. PETA are nothing to be ignored, and honestly, if I were a fishermen I would be concerned too. By implementing these laws they protect their 'right' to fish. I think that both hunting and fishing should be allowed if it is undertaken responsibly. 


The problem is that PETA have made this into an animal cruelty issue when it should be a conservation issue. With these laws in place it would be very difficult for any government agency to reduce fishing if this action was resulting in a significant reduction in fish populations. It is already difficult for these agencies to enforce current regulations to stop recreational fishers from overfishing, and the last thing we need is to make this job even harder! For example, what if fish stocks were depleted in an area and the government agency wanted to stop fishing in that area to help them recover? Fishermen might argue that it is their constitutional right to fish there. Recreational fishermen tend to be very resistant, maybe even a bit touchy, when it comes to other people telling them what they can do with their fish. This can sometimes be despite mounting evidence that that fish stock may be in trouble. One only needs to remember the arguments commercial fishermen made when the scientists told them the cod stocks were running out. 

In the end people need to remember that we all want the same thing. I want to be able to go diving and see fish in their natural environment. Fishermen want to be able to go out and fish. The emphasis should not be on protecting the right of the fishermen, or even PETA's animal cruelty agenda, the focus should be on protecting fish stocks so we can all enjoy them. 

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Tuesday, October 26, 2010

X Fish


Kansas has agreed to designate Xiphactinus or X-fish the states official fossil. This fish was found within a Kansas prairie, which was once covered by water. This was after a petition with over 3000 names on it.

Hmmmm fossils in Kansas how will the creationists feel about that?
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Fish vs. Turtle


Well its high time I did a post. So here is a short one.....but worth it. Bad commentary aside it's worth watching!

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